The invention relates generally to fuel supply systems for internal combustion engines and more particularly to carburetors which form the combustible mixture supplied to the engine independent of the velocity of air flow through the carburetor throat.
The increasing problem of air pollution from automobile exhaust emissions has resulted in stringent new emission controls being placed on the automotive industry. At the same time, the public's desire for greater engine performance and more auxiliary components such as automobile air conditioning have substantially reduced gasoline mileage while fuel costs have risen and supplies are running short. This unfortunate combination of conditions has placed such performance demands on the gasoline powered internal combustion engine that its future usefulness as a power source is presently under question. Since the problems of harmful exhaust emissions are directly related to the efficiency of fuel combustion, carburetor design is receiving considerable attention.
Most gasoline powered automobile engines have, for a number of years, used a venturi type carburetor. In this type carburetor the gasoline is drawn into the throat through venturi jets responsive to the passing flow of air. Under certain operating conditions this means of deriving a combustible mixture has significant limitations. This has resulted in many accessories and modifications being added over the years. In most of todays automobiles, for example, the carburetors include an automatic-thermal responsive choking device and associated fast idle throttle linkage, an idle by-pass system, a high speed jet, an acceleration pump and other similar accessories. These accessories plus the techniques of increasing the throat size, compartmentalizing into "two barrel" and "four barrel" carburetors, and the addition of smog control devices which backfeed exhaust gases, have resulted in extremely complex carburetors which are not only expensive to manufacture and maintain but which have provided only mediocre performance as well.
A need, therefore, exists for an improved carburetor which can meet current requirements for high performance of the engine, and yet provide reasonable economy and reduced harmful exhaust emissions.